The
U.Va. assistant professor of computer science works with
super-sized sets of data to create visual displays,
a process that requires
major computing power.
But instead of looking to traditional solutions – using an expensive
supercomputer to crunch massive amounts of data, or simplifying the problem
by reducing the
amount of data involved – Humphreys has taken a new route. He harnesses
off-the-shelf PCs to work in a “cluster” on separate pieces of
a problem and later puts the pieces back together again. It’s like solving
a giant jigsaw puzzle.

For
his efforts in developing “Chromium” computer
graphics software, Humphreys and a team of collaborators recently won a prestigious
industry award,
the R&D 100. The award, which recognizes the 100 “most technologically
significant new products and processes of the year,” is bestowed annually
by R&D Magazine, a publication based in Oak Brook, Ill., that reports
on applied industrial research.

The
goal of the award program, which reviews a broad array of
technological
innovations each year, is to highlight technology that advances and supports
mankind, said
Tim Studt, editor-in-chief of R&D Magazine and program chairman of
the R&D
100 Awards.

In
nearly every category of analysis, Chromium received top
marks from the judges, he said.

“One
judge called it ‘a killer application for cluster computing,’” Studt
said. “Another judge noted that it was ‘a major advance
in the state of the art,’ and ‘more efficient than anything
else out there.’”

Just
a few years old, Chromium is already widely used by industry,
government agencies and researchers for a
wide range of computer graphics
applications,
especially in manufacturing, defense simulations and medical science.

Humphreys,
who joined U.Va.’s computer science faculty in 2002,
initially developed the “freeware,” or freely
available software, while completing his doctorate in computer
graphics at Stanford University.

What
Chromium does is to break down problems involving big sets
of numbers into
small packets of data, like pieces
of a puzzle. The
data is sent
to a “cluster” of
computers, individual PCs that are linked together in a local-area
network. Each PC is fitted with an off-the-shelf computer graphics
card that processes the
data it was sent, working only on its own little piece of the puzzle.
After the data has been converted into images, Chromium gathers
the data from the individual
computers and sends it to a projector or computer screen for display.
In this way, the whole puzzle can be reassembled by using a number
of projectors to display
the individual puzzle pieces side by side, creating a composite
picture. The data set is re-assembled as a visual display.

“Computer
graphics are easy to explain but hard to do, which is what
attracted me to this subfield of computer science,” Humphreys
said.

One
example of the software’s usefulness is seen
at the Department of Energy, which funded the Chromium
research and development. Under the international nuclear
test ban treaty, the U.S. has agreed not to test its nuclear
weapons. But the government still needs to know if the
stockpile
works. With Chromium, the analysts
hook up a sufficient number of PCs into a cluster, process
the data in pieces, and project it to a screen as a composite
image.

Another
application is appreciated by video-game enthusiasts, who
like to watch video game competitions online.
With Chromium
installed
on
a home computer,
a viewer can watch a game as it’s being played by
professional game players, but change the representation
of art on the
screen into a blueprint style so
that solid planes become open-line drawings, allowing the
enthusiast to see through the roofs and walls of buildings,
observing action that otherwise would be obscured.

One
of the most important applications for this technology is
scientific visualization, Humphreys said. Many scientists
today
run computer
simulations to try to understand
chemical
or biological processes. But their initial results are
often in the form of huge data sets that can be difficult
to analyze
and
interpret.
Using
Chromium in combination
with a computer cluster, they can create meaningful visual
displays.

Chromium
offers two advantages over traditional approaches to computer
graphics, Humphreys said. First, it is cost
effective. Computing
power in off-the-shelf,
personal computers has skyrocketed in recent years,
making a
lot of analytical power available for relatively little
money. Linking
them
together further
increases this capability.

Second,
Chromium offers a way for researchers to create visual displays
of data in
real time without having
to throw out
reams of data to
reduce the
size of
data sets so they can be manipulated quickly and
easily.

Chromium
is not alone in the world of cluster computing, as custom
solutions for specific applications exist,
Humphreys said. But
Chromium is one-of-a-kind
in its use of off-the-shelf hardware to run open-source
software, which is free to the public. And it’s
not copyrighted — users are free to modify
it. In fact, it’s designed to be extended
by its users, he said.

Along
with Humphreys, the other developers named
in the R&D 100 Award for “Chromium:
Parallel, Distributed Open GL Rendering on Commodity
Clusters” were Lawrence
Livermore National Laboratory, Stanford University,
University of Virginia and Tungsten Graphics
Inc. The work recognized in the award was performed
under contract
with the U.S. Department of Energy.

As
if developing computer graphics software weren’t enough
to keep him busy, Humphreys has co-written
a college textbook with Matt Pharr, a fellow graduate
student from his days at Stanford. Five years
in preparation, the book, “Physically
Based Rendering: From Theory to Implementation,” is
appearing this summer as part of the Series
in Interactive 3D Technology by Morgan Kaufmann,
a subsidiary
of Elsevier Global Scientific and Medical Publishing.

Humphrey’s
current research involves developing applications
of Chromium for use in K-12 math and science
education. Through a joint Technology in
Education Program that brings together expertise from
U.Va.’s School of Engineering
and Applied Science and the Curry School
of Education, Humphreys is working to enable
school
systems to provide educational graphics from
a central location.
He’s hoping to make it easy for a school
system to invest in a cluster of computers,
linked by a local-area network and served
by Chromium, to transmit
visual displays for mathematics and other
courses to schools throughout the system.

In
the classrooms, teachers could display
the information on a variety of equipment,
including
inexpensive
computer monitors,
tablet PCs,
personal digital assistants
or a single projector, depending on their
instructional needs.

Looking
ahead, Humphreys believes it likely that in 10 years or so, “most
flat surfaces,” such as walls or
desktops, could be used as visual displays
in the classroom.

He
sees the field of computing coming full circle within 50
years. In the 1960s,
there
was a smaller
number
of huge, central
mainframe
computers.
With the PC
revolution, there was an explosion
of small, but relatively powerful, decentralized
terminals. In the coming years, the
need for increasing power to analyze data
and
create
graphics may lead
again to the
growth of
centralized
computing.

“It
doesn’t make economic sense to continue using powerful
PCs; instead we’ll probably break the coupling
between display and computer,” Humphreys
said. “What’s been holding
us back has been the infrastructure
of remote delivery,” finding
cost-effective ways to deliver content
to computer monitors from a distance.

And
in the coming computer revolution,
Humphreys hopes his path-breaking
software will play
a leading role
in delivering
accurate, affordable
graphics to locations
near and far.

###

SIDEBAR:

A
Brief History of the R&D 100 Awards

The
R&D 100
Awards were established in 1963 as the I-R 100s, in keeping
with the original name of the magazine, Industrial Research.
While initially, only
U.S. companies could win,
the first non-U.S. winners came along in 1965.

Over
the years, the R&D 100 Awards have recognized winning
products with such household names as Polacolor film (1963),
the flashcube
(1965), the automated
teller machine (1973),
the halogen lamp (1974), the fax machine (1975), the liquid
crystal display (1980),
the printer (1986), the Kodak Photo CD (1991), the Nicoderm
antismoking patch (1992),
Taxol anticancer drug (1993), lab on a chip (1996), and
high-density television (1998).